With 1.3 million freight vehicles and trailers passing through the three main Irish ports annually, the Garda and the Revenue’s Custom service face a mammoth task in detecting migrants or contraband, such as drugs and counterfeit cigarettes, being smuggled into the Republic.
Senior Garda officers in particular are very concerned that cases like the discovery of 16 Middle Eastern migrants - all male and two of them juveniles - are about to become more frequent when Britain becomes harder to enter after Brexit.
The concern is that some will come here and apply for international protection with the ultimate aim of catching a ferry to Britain and disappearing there unnoticed and undocumented.
In the case of the 16 males detected in a truck’s trailer on the Stena sailing from Cherbourg to Rosslare on Thursday morning; one of the ferry company’s employees heard the men inside the container and raised the alarm.
But what would have happened had the men gone undetected on board and still been in the container as it was driven off the ferry?
The difficult reality is that they would have had a very good chance of making it through security checks.
Customs scanners represent the best line of defence against undocumented migrants entering the Republic illegally, despite the fact they are intended to detect drugs and other contraband.
There are four scanners in total. The latest model is a truck-based ZBV mobile scanner which can drive past trucks or ground level containers and scan them, anywhere in Dublin Port, where it has been based since January.
While the €1.1 million ZBV scanner is mobile and can scan trucks and containers more quickly, it can only scan a small fraction of the trucks and trailers that pass through Dublin Port.
The other three scanners, which are older models, are based in Dublin Port, Cork and Rosslare. Containers or trucks must be taken to those scanners and run through them, making the process much slower. In reality, only trucks and containers identified through profiling are taken to the three older scanners for checks.
Last year 1.16 million freight vehicles or trailers passed through Dublin, Rosslare and Cork ports as well as 130,000 empty freight containers. Dublin Port accounts for 89 per cent of the total, or just over one million trucks and trailers and 127,000 empty trailers.
Garda sources believe migrants are regularly coming through the ports on container freight undetected in the same way the majority of the illegal drugs and firearms are.
“We check very few of them (containers) for people, or for drugs; there are so many containers coming in through the ports you’d close the country down with delays if you tried to check them all or even if you tried to check half of them.”
However, gardaí believe Britain is a much more popular destination for illegal migrants and the numbers entering Ireland in containers are relatively small, though they have no way to be sure.
While trucks carrying freight are sealed when the containers are loaded, this has not stopped migrants, or the gangs that smuggle and traffic them, bypassing the seals, which snap if the truck’s doors are opened.
In some cases, holes are cut in the roofs of refrigerated containers, or curtain-sided trailers are slashed with knives, allowing people to climb into the containers.